Multiple repeats of Helicobacter pylori CagA EPIYA-C phosphorylation sites predict risk of gastric ulcer in Iran.

ABSTRACT

Biological activity of Helicobacter pylori oncoprotein CagA is determined by a diversity in the tyrosine phosphorylation motif sites. In the present study, the diversity and the type of the H. pylori CagA EPIYA motifs and their association with gastric ulcer (GU) and duodenal ulcer (DU) in Iranian dyspeptic patients were assessed. PCR amplification, sequencing, and bioinformatic analysis were performed to determine the pattern of CagA EPIYA motifs. Of 168 H. pylori cagA(+) strains, the frequency of ABC was 93.50%, ABCCC 5.40%, ABC + ABCCC 0.6% and ABCC 0.6%. There was no EPIYA-D segment. The ABCCC pattern of EPIYA motif was more frequent in the H. pylori isolates from GU (8/50, 16%) than in those from chronic gastritis (CG) (0/81, 0%) (P = 0). In contrast, The ABC pattern of EPIYA motif was less frequent in the H. pylori isolates from GU (41/50, 82%) than in those from CG (80/81, 98.80%) (Age-sex-adjusted odds ratio (OR) = 0.020, 95% CI = 0.002-0.259; P = 0.003). The distribution of the ABC motif was almost the same in H. pylori isolates from CG (98.80%) and DU diseases (97.30%). There was no significant association between the number of CagA EPIYA-C segment and DU (P > 0.05). We have proposed that CagA from Iranian H. pylori strains were Western type and all strains had active phosphorylation sites. The three EPIYA-C motifs of CagA were more frequently observed in the H. pylori strains from GU; thus it might be an important biomarker for predicting the GU risk in Iran.